30 CRUCIFER.E. (MUSTARD FAMILY.) 



1. NASTURTIUM, R. Br. WATER-CUESS. 



Pod a short silique or a silicic, varying from oblong-linear to globular, terete 

 or nearly so, often curved upwards : valves nerveless. Seeds small, turgid, 

 marginless, in 2 irregular rows in each cell. Cotyledons accumbcnt. Aquat- 

 ic- or marsh plants, with yellow or white flowers, and pinnate or pinnatifid 

 h-aves, usually glabrous. (Name from Nasus tortus, a convulsed nose, alluding 

 t> the effect of its pungent qualities.) 



1. Petals white, tw'.ce the length of the calyx : pods linear: leaves pinnate. 



1. IV. OFFICINALE, R. Br. (WATER-CRESS.) Stems spreading and root- 

 ing; leaflets 3- 11, roundish or oblong, nearly entire; pods (6" -8" long) on 

 slender widely spreading pedicels. 1J. Brooks and ditches; rare: escaped 

 from cultivation. (Nat. from Eu.) 



$ 2. Petals ydlow or yellowish, seldom much exceeding the calyx : pods linear, oblong, 

 ovoid, or ylobular: leaves mostly pinnatijid. 



# Perennial from creeping or subterranean shoots: flowers rather large, bright yellow. 



2. IV. SYI.VESTRE. R. Br. (YELLOW CRESS.) Stems ascending; Itaves 

 pinnate/y parted, the divisions toothed or cut, lanceolate or linear ; pods linear 

 (4" -6" long), on slender pedicels; style very short. Wet meadows, near Phila- 

 delphia ; and Newton, Massachusetts, C. J. Sprague. (Adv. from Eu.) 



3. IV. SiiBiiatlim, Nutt. Stems low, diffuse ; l-avcs pimmtdy cleft, the 

 short lobes nearly entire, linear-oblong ; pods linear-oblong (4"-6" long), on 

 slender pedicels ; style slender. Banks of the Mississippi and westward. J.uue. 



* * Annual or biennial, rarely perennial? ivrth simple fibrous roots : flowers small 



or minute, greenish or yellowish : leaves somewhat It/rate. 



4. TV. Mvssiliflormii, Nutt. Stems erect, rather simple; leaves obtusely 

 incised or toothed, obovatc or oblong ; Jlowers minute., nearly sessile ; pods elon- 

 gated-oblong (5" -6" long), thick; style very short. With No. 3 and south- 

 ward. April -'June. 



5. IV. ohtiismn, Nutt. Stems much branched, diffusely spreading ; 

 //".s /n'lUKiti'/i/ purttd or dicidi-.d, the divisions roundish and obtusely toothed or 

 rcpaiid ; Jlowers minute, short -pr dicelled ; pods longer than the jxd/i'L-Ls, varying 

 from linear-oblong to short-oval; style short. With No. 3 and 4. 



6. IV. p.iliistre, DC. (MARSH CRESS.) Stem erect; lent PS pinnatcly 

 cleft or ported, or the upper laciniate ; the lobes oblong, cut-toothed ; pedicels 

 (ilunt <is lout] as thi' si/mil fimrcrs and mostly longer than the oblong, ellipsoid, or 

 ovoid /**/.>> ; style short. Wei ditches and borders of streams, common. June 

 -Sept. Flowers only l"-lj" long. Stems l-3 high. The typical form 

 with oblong pods is rare (W. New York, l)r. Sartirell). Short pods and hirsute 

 stems and leaves are common. Var. iiisrlouM (N. hispidum, DC.) is this, 

 with ovoid or globular pods. (Eu.) 



t 3. Pi tula ti'hite, mnrh lonucr than the calyr : pods oroid or globular : bares undi- 



mtid, or tin', hirer ones pinmitijid. ( Armoracia.) 



*. IV. Inn'istrr, Gray, Gen. 111. 1, p. 132. (LAKK CHESS.) Aquatic, 

 immersed leaves 1 -3-pinnately dissected into iitinieroiis caj>illary <livi>ions ; 

 emersed leaves oblong, entire, serrate, or pianatitid ; j>edicels widelj spreading ; 





